Get your HBT Growlers, Shirts and Membership before the Rush!


Home Brew Forums > Home Brewing Beer > Brew Science > Counting Yeast Cells
Reply
 
LinkBack Thread Tools
Old 01-23-2010, 02:28 AM   #1
Netflyer
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Netflyer's Avatar
Recipes 
 
Join Date: Oct 2009
Location: Near Benedict Maryland
Posts: 812
Liked 8 Times on 8 Posts
Likes Given: 45

Default Counting Yeast Cells

The Wyeast Smack pack says 100 billion yeast cells... I suppose that is after it has swollen?

So if I use this and create a starter, with 3/4 wort and 3 cups of water to yield about an 800ml 1.040 starter. What kind of yeast growth can be expected over say 24 hours? Will the yeast double? More than double? How can you calculate or measure? Using a stir plate with the starter.

Thanks for any help!

__________________
Primaries:


Kegged:
RiClarke's Guinuess Clone w/da sour 6.4% ABV 1057 SG 1009 FG

Netflyer is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 02:35 AM   #2
Edcculus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2007
Location: Greenville, SC
Posts: 4,567
Liked 42 Times on 39 Posts

Default

It contains that before it swells. Smacking the pack does not grow cells, it just proofs them.

The Mr. Malty yeast calculator is really the best tool to figure this stuff out.

Labs usually measure cell count with a densitometer. Yeast viability is measured by methylene blue dye and counting under a microscope.

__________________
Edcculus is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 12:39 PM   #3
Netflyer
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Netflyer's Avatar
Recipes 
 
Join Date: Oct 2009
Location: Near Benedict Maryland
Posts: 812
Liked 8 Times on 8 Posts
Likes Given: 45

Default

I was afraid you would say that ... years ago, maybe 30 I used those tools in the lab to count bacteria. I was just hoping there might be a better way to figure out how many cells you have. Mr. Malty is actually what got me thinking about this. My question really is: in 24 hours if you put 1 billion yeast cells in a 1.040 wort in a 1L flask on a stirplate, wouldn't the yeast have an exponential growth and number in the 10's of billions by then?

I ask because I don't really understand why I would pitch a starter over 1L ever. For a 1.070 wort and 5 gal Mr. M wants me to pitch about 1.5L or 250 billion cells. How can it be that 1 billion cells goes through a complete krausening on a stirplate over 24 hours and doesn't at least triple. I'm thinking it does way more than triple though. I guess I'm off to go research yeast growth rates.

__________________
Primaries:


Kegged:
RiClarke's Guinuess Clone w/da sour 6.4% ABV 1057 SG 1009 FG

Netflyer is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 04:33 PM   #4
Edcculus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2007
Location: Greenville, SC
Posts: 4,567
Liked 42 Times on 39 Posts

Default

I think you are on the right track, except for the fact that over that 24 hours, the yeast aren't multuplying. They go through their initial exponential growth phase, which is prolonged by a stirplate, then go into their respiration phases. A starter is as much about growing yeast as making sure they are very healthy. I'm not sure I completely understand growth rates, but I know Jamil has done extensive research on his own, and with Wyeast to determine these pitching rates.

Also, for large starters, you could stick it in the fridge for 24 hours, then decant off the liquid.

__________________
Edcculus is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 05:24 PM   #5
Hermit
Feedback Score: 0 reviews
Recipes 
 
Join Date: Nov 2009
Location: Alternate Universe
Posts: 2,249
Liked 67 Times on 57 Posts
Likes Given: 10

Default

Quote:
Originally Posted by Netflyer View Post
I was afraid you would say that ... years ago, maybe 30 I used those tools in the lab to count bacteria. I was just hoping there might be a better way to figure out how many cells you have. Mr. Malty is actually what got me thinking about this. My question really is: in 24 hours if you put 1 billion yeast cells in a 1.040 wort in a 1L flask on a stirplate, wouldn't the yeast have an exponential growth and number in the 10's of billions by then?

I ask because I don't really understand why I would pitch a starter over 1L ever. For a 1.070 wort and 5 gal Mr. M wants me to pitch about 1.5L or 250 billion cells. How can it be that 1 billion cells goes through a complete krausening on a stirplate over 24 hours and doesn't at least triple. I'm thinking it does way more than triple though. I guess I'm off to go research yeast growth rates.
I've had questions about Mr. M myself. Almost sounds as if he is assuming there is a maximum density the yeast can reach?
__________________
Hermit is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 05:56 PM   #6
Netflyer
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Netflyer's Avatar
Recipes 
 
Join Date: Oct 2009
Location: Near Benedict Maryland
Posts: 812
Liked 8 Times on 8 Posts
Likes Given: 45

Default

Well, as far as max density, there are limiting factors. The amount of sugar will run out, the alcohol will cause the yeast to stop growing and multiplying, etc etc. I have been searching for good growth curves of yeast and it is hard to find a curve with just yeast in a wort. Most curves you find on the net are yeasts with other factors to test the way those factors limit the growth. It does seem though that the ratio of growth over 24 hours is about 2-4x as many cells as when the yeast were started. As for the Wyeast density, there may be 1 billion cells in that pack but the density is 6 million per ml. So another question arises about density per ml and the whole starter... When Mr. M has you make a 2 L starter that means 2L of wort, not 2L of yeast. I pitch my whole starter in the cooled wort instead of decanting liquid off the top and just attempting to pitch the yeast. My worts start to ferment in under 4 hours, and usually w/in 2 hours. Wyeast recommends 2 smack packs over 1.070 and 3 over 1.080 or the use of a starter...

I still think you can more than double your number of cells from a Wyeast smack pack using a stirplate in 24 hours...

__________________
Primaries:


Kegged:
RiClarke's Guinuess Clone w/da sour 6.4% ABV 1057 SG 1009 FG


Netflyer is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 05:57 PM   #7
Edcculus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2007
Location: Greenville, SC
Posts: 4,567
Liked 42 Times on 39 Posts

Default

Quote:
Originally Posted by Hermit View Post
I've had questions about Mr. M myself. Almost sounds as if he is assuming there is a maximum density the yeast can reach?
I'm assuming there is. If there weren't, then you could grow seventy quadruplebillion cells in 2 oz of wort. Obviously, thats not the case. Since you pretty much keep the gravity constant, bigger starter=more yeast. Wyeast also has a similar calculator which works a little differently. I'm almost positive its based pretty closely off of Jamil's.

Jamil comes around the forum every once and a while. Pretty sure his username is JamilZ. Think he has slacked off a little since the whole "I'm a Homebrewer" incident though.

You can also contact him at jamil@thebrewingnetwork.com. He may take a while, but he is pretty good at getting back to people.
__________________

Edcculus is offline
 
Reply With Quote Quick reply to this message
Old 01-23-2010, 06:02 PM   #8
Edcculus
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2007
Location: Greenville, SC
Posts: 4,567
Liked 42 Times on 39 Posts

Default

Quote:
Originally Posted by Hermit View Post
I've had questions about Mr. M myself. Almost sounds as if he is assuming there is a maximum density the yeast can reach?
Jamil comes around the forum every once and a while. Pretty sure his username is JamilZ. Looks like he is still active. Forum search - member JamilZ. Maybe he'll make his way here and clear some things up. I'm just kind of spouting off info I've heard in podcasts etc.

You can also contact him at jamil@thebrewingnetwork.com.
__________________
Edcculus is offline
 
Reply With Quote Quick reply to this message
Old 01-25-2010, 01:51 AM   #9
nealperkins
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
nealperkins's Avatar
Recipes 
 
Join Date: Oct 2007
Location: Boone, NC
Posts: 302
Liked 13 Times on 11 Posts
Likes Given: 6

Default

I hope you keep pushing for specifics on this subject. I for one, would really like to have more definitive information.

It all seems quite fuzzy to me an that's after asking some specific questions directly to Chris White (I'm sure he knows, and some how it's my fault but...)

What about stir plates? Add continuous aeration? How about some SPECIFICS ALREADY!! (read frustration here.)

Thanks

__________________
nealperkins is offline
 
Reply With Quote Quick reply to this message
Old 01-25-2010, 02:58 AM   #10
Netflyer
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Netflyer's Avatar
Recipes 
 
Join Date: Oct 2009
Location: Near Benedict Maryland
Posts: 812
Liked 8 Times on 8 Posts
Likes Given: 45

Default

From the Wyeast website:

http://www.wyeastlab.com/hb_pitchrates.cfm

Check out the pitching rates they recommend... Keep in mind that:

Activator Package:

The Wyeast Activator (125 ml) smack-pack is designed to directly inoculate 5 gallons of standard ale wort (O.G. < 1.060, 65-72°F). When brewing high gravity beer (O.G. >1.060) or cold fermented lagers or ales (<65 °F)) additional yeast will be required. An Activator contains approximately 100 billion cells which will deliver slightly less than 6 million cells per milliliter to a 5 gallon batch of beer.

So this means their 1 billion cells pack delivers 6 million cells per ml to a 5 gallon batch... if you make a starter you can use their pitching calculator to see what size starter you would need for the gravity you want:

http://www.wyeastlab.com/hb_pitchrate.cfm

So basically if I need 12-13 million cells per ml for a 1.07 to 1.078ish wort, you can mess with the pitchrate calculator to see how large of a starter you need. I must say this corresponds very nicely to the amounts Mr. Malty suggests (as it should). Basically by deduction we can see that it is possible to at least double the amount of cells we start with because the Wyeast site calculator is based upon 24-36 hours of growth.

This is important too (also from the Wyeast site:
A low pitch rate can lead to:

  • Excess levels of diacetyl
  • Increase in higher/fusel alcohol formation
  • Increase in ester formation
  • Increase in volatile sulfur compounds
  • High terminal gravities
  • Stuck fermentations
  • Increased risk of infection
High pitch rates can lead to:
  • Very low ester production
  • Very fast fermentations
  • Thin or lacking body/mouthfeel
  • Autolysis (Yeasty flavors due to lysing of cells)
So as much as a short lag phase is very desireable it seems that we don't want to over shoot that or we can end up in trouble too...
__________________
Primaries:


Kegged:
RiClarke's Guinuess Clone w/da sour 6.4% ABV 1057 SG 1009 FG

Netflyer is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Maximizing yeast cells jamesrm General Techniques 3 03-03-2009 02:52 PM
How many yeast cells are in a 5 g batch :-) Grinder12000 General Beer Discussion 9 02-05-2009 09:54 PM
Yeast counting WBC Equipment/Sanitation 8 10-07-2008 10:36 PM
How many cells in my yeast? gravity man Recipes/Ingredients 2 04-20-2008 10:46 PM
Sufficient Yeast Cells In Suspension After Lagering? Evan! General Techniques 12 11-01-2006 06:32 PM



Newest Threads

LATEST SPONSOR DEALS